Various methods of imparting information to documents have been proposed. For example, negotiable instruments have been provided with tamper evident systems to indicate when alteration is attempted. Such systems are described in the "Background of the Invention" section of U.S. Pat. No. 5,427,415.
Likewise, hidden entry systems have been proposed for imparting information as described in the "Background of the Invention" section of U.S. Pat. No. 5,344,191.
Many of the prior systems involve use of extraneous fluids, including chemicals or inks to impart information. Accordingly, a need exists for a simple and efficient system which is able to impart information to documents.